Vehicles may use pressure relief valves, also known as air-extractors, to influence air flow from the vehicle cabin to enhance passenger comfort. As a climate control system takes in ambient air from outside the vehicle, air exhaustion through the pressure relief valves may be required to attain proper circulation and reduce cabin pressure build-up.
Passive pressure relief valves for venting pressure from an automotive cabin are known in the art. The pressure relief valves are typically a plastic housing with an elastomer flap that opens when the interior pressure is greater than the exterior pressure. The greater interior pressure forces the flap open and cabin air is exhausted through the valve until the pressure is equalized. Once pressure is equalized the flap closes under its own weight. Flaps typically rely on gravity to remain closed. This valve design is susceptible to noise and exterior elements entering the passenger compartment through the air-extractor when the vehicle is moving. To reduce the amount of noise and exterior elements from entering the cabin, the passive pressure relief valves are designed as small as possible which limits the rate at which the pressure relief valve may equalize pressure.
When cabin-doors are closed, a sudden pressure rise may be created. Cabin-door closure builds air pressure within the cabin rapidly resulting in high closing efforts and potential discomfort to passengers. Current pressure relief valves may not be able to relieve the cabin pressure build-up fast enough. If current pressure relief valves are able to relieve the cabin pressure fast enough, then the size of the pressure relief valve may allow for more noise and exterior elements to enter the cabin than desired. Either way, the current pressure relief valves require a tradeoff that may not be desirable to the drivers or passengers of the vehicle.